1. Field of the Invention
The present invention relates to a projection display device for modulating light from a light source, and enlarging and projecting the modulated light.
2. Disclosure of Related Art
A high luminance light source such as a metal halide lamp or a high pressure mercury lamp is used in a projection display device such as a liquid crystal projector. The light source is provided with a lamp (arc tube) and a reflector, and is constructed to reflect light emitted from the lamp on the reflector and emit the reflection light in the forward direction. Since the light source is heated to a high temperature at the time of light emission, it is necessary to cool the light source by a cooling device.
In the above case, it is possible to use an arrangement, wherein a cooling air is supplied to the interior of the reflector to cool the lamp. In this arrangement, plural cooling fans are disposed, and a cooling air generated by each of the cooling fans is drawn into the interior of the reflector in two different directions to prevent lowering of the cooling performance of the light source, even if the projector is installed in various postures.
A fixing portion (called as a reflector base) made of e.g. plaster is provided at a rear end of the reflector to fixedly mount the lamp with respect to the reflector. The lamp has a seal portion at an inner position of the reflector base. When light from the lamp is emitted, the seal portion is heated to a high temperature by heat generation of the lamp. If the seal portion is exceedingly heated, the seal portion may be deteriorated, with the result that the performance of the light source may be deteriorated.
Since the seal portion is disposed at a position relatively away from the inner surface of the reflector, the seal portion may not be sufficiently cooled, even if the cooling air is draw into the interior of the reflector, as proposed in the aforementioned projector. In this case, it may be possible to enhance the cooling performance by increasing the air volume of the cooling air. However, an enhanced cooling performance may excessively cool the lamp, which may obstruct a normal light emission.